膜下滴灌水稻生理生化特性对灌浆期控水的响应

【目的】 研究膜下滴灌水稻叶片生理生化特性和产量对灌浆期控水的响应，为干旱区水稻节水栽培提供理论依据。【方法】 以田间持水率（θs）为参考，水稻灌浆期设置90%θs（W₁）、80% θs（W₂）和70% θs（W₃）的3种不同灌水控制下限，以常规淹灌为对照（CK），研究不同水分条件对水稻的光合特性、保护酶活性、渗透调节物质、根系活力、产量和水分利用效率的影响。【结果】 灌浆期控水会导致水稻的光合作用减弱，与对照（CK）相比，叶片净光合速率（P_n）、蒸腾速率（T_r）、气孔导度（G_s）和胞间CO₂浓度（C_i）分别下降15.12%~72.38%、25.32%~67.59%、5.93%~24.34%和29.62%~62.61%。灌浆期控水可增强水稻抗氧化系统酶活性，W₃的SOD、CAT和POD均最高，比CK依次高出77.78%、24.64%和14.24%。在灌浆期，控水下限越低，可溶性糖含量、脯氨酸含量越高，可溶性蛋白越低；W₃的可溶性糖含量是其他处理的1.35~2.32倍，CK可溶性蛋白含量高出控水处理6.72%~25.24%。CK最高产量为8 222.12 kg/hm²，比W₁、W₂、W₃增产16.37%~59.96%。与CK相比，控水处理耗水量下降56.06%~61.66%，水分利用效率提高38.65%~48.79%。【结论】 膜下滴灌水稻灌浆期控水对水稻的生理生化特性及稻米品质影响负显著，不宜控水，灌浆期灌水上下限分别设为5和10 cm水层，可保证水稻优质高产。

Hysiological and Biochemical Characteristics of Rice under Mulch Drip Irrigation with Different Water Controlin the Filling Stage

【Objective】 The effect of water control on rice during grain-filling stage was studied in this paper，providing a theoretical support for water-saving rice cultivation in arid areas. 【Methods】 At rice filling stage，three lower limits of irrigation control were set：90% θs （field water-holding capacity），80%θs and 70% θs （marked as W₁，W₂ and W₃，respectively），and conventional flood irrigation was set as control （marked as CK）. The photosynthetic characteristics，protective enzyme activities，osmotic adjustment substances，root activity，yield and water use efficiency of rice under different water conditions were compared. 【Results】 Water controlwould weaken photosynthesis of rice in the filling stage. The results showed that the P_n （net photosynthetic rate），T_r（intercellular carbon dioxide concentration），G_s（stomatal conductance） and C_i（Intercellular carbon dioxide concentration） decreased by 15.12%-72.38%，25.32%-67.59%，5.93%-24.34% and 29.62%-62.61%，respectively. Water control can enhance the enzyme activity of rice antioxidant system in the filling stage. SOD，CAT and POD of W₃ were the highest，which were 77.78%，24.64% and 14.24% higher than those of CK. In the filling stage，the lower the water control limit，the higher the soluble sugar content and proline content，the lower the soluble protein content. The soluble sugar content of W₃ was 1.35-2.32 times of that of other treatments，and the soluble protein content of CK was 6.72%~25.24% higher than that of the three water control treatments. The highest yield of CK was 8 222.12 kg/hm²，which was 16.37%~59.96% higher than that of W₁，W₂ and W₃. Compared with CK，water consumption for W₁，W₂ and W₃ decreased by 56.06%~61.66%，and water use efficiency increased by 38.65%~48.79%. 【Conclusion】 Water control during grain filling period under mulch drip irrigation has a negative effect on physiological and biochemical characteristics and rice quality，and it is not suitable to control water. During the grain filling period，the upper and lower limits of water control were set to 5 cm and 10 cm，respectively，to ensure high quality and high yield of rice.